The invention relates to an energy guiding chain for guiding cables, hoses and the like, having a number of chain links connected to one another in articulated fashion which are formed by parallel straps connected by cross-members, which energy guiding chain can be moved in such a way that it forms an upper strand, a lower strand and a deflection zone connecting the two, where the upper strand rests on the lower strand, and where at least some of the chain links of the upper strand and/or the lower strand are provided with rollers which are arranged in such a way that, when the energy guiding chain travels, they can roll on running surfaces provided on the chain links of the opposite strand.
Furthermore, the invention relates to an energy guiding chain for guiding cables, hoses and the like, having a number of chain links connected to one another in articulated fashion which are formed by parallel straps connected by cross-members, which energy guiding chain can be moved in such a way that it forms an upper strand, a lower strand and a deflection zone connecting the two, where the upper strand rests on the lower strand.
In some applications, energy guiding chains of this kind are of a considerable length which can be in the region of 100 meters or more. Thus, the drive must provide correspondingly high drive power in order to move the energy guiding chain. This is especially the case if the upper strand of the energy guiding chain rests on the lower strand during travel, as the corresponding sliding friction, which reaches a substantial magnitude with very long energy guiding chains, has to be overcome. The respective sliding surfaces of the chain links are subject to increased wear due to the friction between the upper strand and the lower strand.
As considerable tensile forces are required to move the energy guiding chain, a change in length also occurs in the energy guiding chain which can easily amount to up to roughly 8%, referred to the length of the unstressed chain. This change in length occurs as a result of the ever-present play between the chain links and the ever-present elasticity of the chain links. This elongation of the energy guiding chain generates corresponding stress on the hoses or the like guided by the energy guiding chain.
It is common practice to provide special support structures for particularly long energy guiding chains that support the upper strand so that the upper strand can be moved on this support structure. In order to facilitate the movement of the energy guiding chain, some of the chain links are provided with rollers that can roll along the support structure. However, the arrangement of support structures of this kind is very complex and, in addition, the support structure cannot be used when moving an energy guiding chain in which the upper strand is arranged above the lower strand. In this case, it has been proposed to design the support structure in such a way that the supporting members can be swung out to the side in order to be removed from the range of motion of the energy guiding chain. However, this requires a corresponding swivel mechanism, which requires appropriate maintenance and also restricts the travel speed of the energy guiding chain. On the whole, there are many fields of application of energy guiding chains in which support structures are not expedient, quite apart from the technical resources they require.
GB 1 444 307 A discloses an energy guiding chain in which the chain links are provided with supporting areas which are oriented in such a way that they combine to form a flat surface. The supporting areas are provided at the inner side of the loop of the energy guiding chain. Predetermined chain links are provided with supporting wheels which protrude beyond the plane of the adjacent supporting area, through a recess provided in the supporting area. An energy guiding chain is thus provided by means of which the supporting forces can be dissipated via the chain links in a favorable manner so that the chain links can be of light construction and higher supporting forces can be distributed.
The object of the present invention is to design an energy guiding chain in which the upper strand can be moved lying on the lower strand with the least possible power and low wear, and which is of the simplest possible design, and by which a simply constructed guidance of the energy transmission chain is provided, even in case of long energy guiding chains.
According to the invention, the object is solved in that the rollers have a guide profile, which is formed by several circumferential guide grooves positioned at a distance from one another in the running surface of the rollers. By these features of the rollers according to the present invention the travel characteristics can be further improved and an emission of noise can be further reduced, furthermore, friction between the lower strand and the upper strand can be lowered. Simultaneously, a reliable guidance of the energy guiding chain is provided.
Furthermore, it is an object of the present invention to provide an energy guiding chain having increased stability of the chain links, especially in case of long chain links.
According to the invention, this object is solved in that two cross-members at a distance from one another in the longitudinal direction of the chain are provided on one narrow side of a chain link.
When the rollers of two chain links equipped with rollers running on top of one another meet, they become offset by roughly the width of one groove due to the geometry of the guide grooves, so that the profiles of the meeting rollers mesh. The elasticity of the energy guiding chain easily permits the upper strand and the lower strand to run slightly offset relative to one another. This offset roughly corresponds to the width of one guide groove. This advantageously prevents the convergence of the two superposed strands when two rollers meet.
It is particularly advantageous if the depth of the guide grooves is at least equal to the distance the roller projects beyond the running surface of the associated chain strap. The rollers then need no longer climb up and down one another, and a considerable amount of tensile force that would otherwise have to be applied to the upper strand is eliminated. Approaching rollers can simply pass through one another.
The guide grooves are expediently provided with a roughly trapezoidal cross-sectional profile, which ensures the correct alignment of the rollers relative to one another.
In this context, the rollers in the sense of the invention should be taken as being elements that rotate when they contact the running surfaces and move relative to them. For example, areas on the chain straps projecting out to the side can be provided as running surfaces.
As a result of these measures, the upper strand can travel directly on the lower strand by means of the rollers, while the friction between the upper strand and the lower strand is dramatically reduced due to the rollers provided in accordance with the invention. For example, the friction of the energy guiding chain according to the invention is roughly 6 or more times less than that of a conventional energy guiding chain of similar design, meaning that the chain can be 6 or more times longer with the same drive.
Furthermore, as a result of the rollers provided, there is considerably less elongation of the chain as compared to conventional energy guiding chains travelling at the same speed. The wear on the contact surfaces between the upper strand and the lower strand is also markedly reduced.
As the running surfaces for the rollers of the opposite strand are located directly on the chain links, it is possible to design the energy guiding chain to be particularly lightweight, meaning that the length of the energy guiding chain and its travel speed can be correspondingly high.
The rollers can be directly mounted on the chain straps using appropriate bearings, and the roller mount can be correspondingly stable. Thus, separate connectors are not required.
The rollers are preferably located in recesses provided on the chain straps, with the rollers projecting at least slightly beyond the chain straps towards the opposite strand. The axis of rotation of the rollers is located inside the cross-section of the chain straps.
The running surfaces for the rollers can be directly formed by the narrow sides of the chain straps facing the opposite strand. In this context, the chain straps can be designed in such a way that a continuous running surface is formed when the energy guiding chain is extended, so that there are no or only slight differences in the level of the running surface, particularly in the joint sections of the chain straps.
The recesses for accommodating the rollers in the chain straps can be of closed design in the lateral direction of the chain straps, i.e. perpendicular to the longitudinal direction of the energy guiding chain. The pockets formed in this way, which are only open to one side, make it possible to design an energy guiding chain with a completely enclosed interior.
In order to ensure minimum surface pressure on the running surfaces, the width of the rollers should be as large as possible. To this end, the chain straps can, if necessary, be provided with wider sections of corresponding width in the region of the rollers, where the wall thickness of the chain straps can decrease towards the joint sections or towards the longitudinal center of the chain straps.
One, two or more rollers can be provided on each narrow side of the chain straps, the rollers being spaced apart from one another in the longitudinal direction of the energy guiding chain, so that the stress on the rollers and the bearings can be distributed over several different rollers in each case.
The straps can be connected by a cross-member positioned in the middle of the chain strap or midway between the two or more rollers, as appropriate. The narrow sides of opposing straps are preferably connected by two cross-members, which can, in particular, be located on the side straps immediately adjacent to the joint or end sections, thus increasing the stability of the chain links, particularly in the case of long links. In this way, the straps can be connected by four cross-members or, if appropriate, by only three or two cross-members. It is particularly advantageous for the cross-members to be provided with wider sections on the side, which partially cover the inside of the adjacent strap. If top and bottom elements are to be provided on the cross-members, so that a completely closed cable channel results, the distance between adjacent cross-members on one narrow side of the straps and the strap length are advantageously twice as large as on the chain links without rollers. The links provided with rollers can thus be fitted with twice as many standard top and bottom elements as the links used previously, in order to form a closed channel without requiring special parts.
In another configuration, each chain strap can be provided with at least one roller mounted in the middle of the chain strap, with cross-members arranged in front of or behind the roller in the longitudinal direction of the energy guiding chainxe2x80x94preferably in front of and behind it. A configuration with several cross-members is particularly advantageous if the chain straps are longer due to the rollers mounted on them.
In order to improve the travel characteristics of the energy guiding chain, the running surfaces can have run-up bevels rising towards the rollers. In this way, the height of the rollers projecting beyond the chain straps can be reduced for any given arrangement of the axis of rotation, this having an advantageous effect on the quiet running of the energy guiding chain.
In order to mount the rollers in the recesses of the chain straps, flanges can be provided which have a bearing section for the rollers, where the flanges can have sections of greater radial dimensions in relation to the axis of rotation of the rollers, these sections being provided with means for attaching the flanges to the chain straps. The rollers can be mounted on one or both sides of the flanges. The axles can also be mounted on one side of the flange and on the opposite section of the chain strap.
If the chain straps are provided with recesses for accommodating the rollers, means can be provided with which the recesses can be bridged on the side towards the opposite strand. This can be achieved by using corresponding caps, for example. This can prevent the rollers of one strand from running into recesses in the chain links of the opposite strand, if no rollers are mounted in these recesses.
In particular, standard chain links can also be provided between the chain links with rollers. In this way, the energy guiding chain can essentially consist of the previously known chain links, between which chain links additionally provided with rollers are mounted at intervals of several chain links, for example.
The chain straps can also be alternatively or additionally designed in such a way that they are provided with recesses for accommodating rollers on one of the narrow sides running parallel to the longitudinal direction of the chain, where the opposite narrow side of the chain strap has no recesses, and where the chain straps are designed in such a way that they can be mounted with either of the narrow sides facing the opposite strand. The same chain strap can thus be optionally used for assembly with or without rollers. For this purpose, the chain strap need only be rotated 180xc2x0 about its longitudinal axis, or about the axis which extends through the center plane of the chain straps perpendicular to their longitudinal direction.
The links with rollers have a greater length, i.e. a greater pitch than the conventional chain links. Exceeding certain pitch dimensions is not desirable, as this generates uneven running of the chain through the deflection radius, especially when links with very different lengths are connected in alternating fashion. Therefore, one configuration of the invention provides that the rollers be mounted on the side of the chain straps projecting outwards and that wider sections of the chain straps projecting out to the side be provided as running surfaces. In this way, the pitch of the chain links without rollers can be retained on chain links with rollers.
In a configuration of the energy guiding chain such as this, at least all the chain straps of one strandxe2x80x94both the outer and inner strapsxe2x80x94are expediently provided with a wider section which forms a running surface, so that at least one essentially closed running surface is formed along the length of the energy guiding chain.
Each of the rollers can penetrate a window-like recess in the wider sections which form the running surfaces.
The rollers can be distributed over the chain links in different ways. It is not always necessary to provide every chain link with rollers, so the rollers can also be mounted on the energy guiding chain at intervals of more than one chain link. In this context, an equal distance can be provided between the rollers so that, for example, only every fourth, fifth, etc. chain link is provided with opposing rollers.
However, the rollers can also be distributed over the length of the energy guiding chain at irregular intervals. Thus, the rollers can be distributed at greater repeat periods, within which the distance between the rollers can, for example, alternate, so that, starting at one chain link, rollers can be mounted after three, then five, then three chain links, etc., in the longitudinal direction of the chain. In this context, the distribution of the rollers over the chain links can also be random.
In addition, it is not necessary to provide both chain straps of the same chain link with rollers, meaning that the distribution of the rollers over the various strands of chain straps need not be symmetrical.
An irregular or asymmetrical distribution of the rollers has the advantage that, at certain times during the movement of the energy guiding chain, not all the rollers are in contact with one another simultaneously, but rather only a few of them, where the time between contact of the rollers can vary. In this way, the slight jolts caused by the meeting of the rollers can be distributed irregularly over the energy guiding chain, so that jerky movements along the entire length of the energy guiding chain can be avoided when it is travelling rapidly. This can improve the quiet running of the energy guiding chain.
Depending on the operating conditions of the energy guiding chain, the chain straps can be provided with rollers that project beyond the longitudinal axis of the chain straps on one side, on the opposite side, or on both sides of the chain straps. In this way, these rollers can be optionally mounted in the region of the upper strand or the lower strand or, if the energy guiding chain can move on both sides of the end point, on both sides of the chain straps.
It is also particularly possible to provide rollers on energy guiding chains that have more than two parallel strands of chain straps, in which case rollers are to be provided on at least two strands. For example, the rollers can be located exclusively on the outer strands, and they can instead or additionally be provided on one or more of the inner strands of chain straps.
It is particularly advantageous if, in at least one area of the chain adjacent to the moving driver of the energy guiding chain, sections of chain links are interconnected, and the chain link closest to the driver is connected to the driver in tension-resistant fashion by at least one element which is essentially inextensible in the longitudinal direction of the chain and flexible in the bending direction of the chain. An element of this kind is described in German Patent Application DE 198 07 083, the entire contents of which are incorporated herein.
Because of the arrangement of the inextensible element on the energy guiding chain in combination with the arrangement of the rollers, the chain can be moved over very great lengths with minimum power and without elongating the energy guiding chain under tensile stress. This generally enables energy guiding chains of particularly great length to be controlled and thus opens up new fields of application for energy guiding chains.
The sections in which the chain links connected by one or more inextensible elements are arranged advantageously comprise several chain links. The sections can be of equal or unequal length. Unequal lengths are preferably used, with the sections becoming shorter towards the driver, because the tensile stress on the chain increases towards the driver.
The inextensible element, or at least one of them if there are several, can be one of the lines guided in the chain. The inextensible element, or at least one of the inextensible elements, is preferably arranged separately from the lines. The element or elements arranged separately from the lines can be provided in the interior of the chain and consists of steel cables, for example. However, any other kind of element that displays these characteristics is also conceivable.
Adjacent ones of the chain links located at the ends of the individual sections are preferably interconnected, and the closest of these chain links to the driver if preferably connected to the driver in tension-resistant fashion by at least one element which is inextensible in the longitudinal direction of the chain and flexible in the bending direction of the chain.
The inextensible element(s) is/are preferably mounted in tension-resistant fashion on strips arranged separately from the cross-members, the strips being connected to the opposing straps of the chain links.
The lines guided through the chain are advantageously secured to these strips by clamps, which can also be provided with fastening elements for the ends of the steel cables or other appropriate inextensible elements.
The strips can have pins on the ends lying in the transverse direction of the chain, which assume the function of link pins for the associated chain links. This means that the pins on the straps form a positive connection by reaching through two aligned openings in the overlapping areas of directly adjacent chain links and thus form the hinge axes between these chain links. This configuration permits the lines and the separate inextensible elements mounted on the strips to be arranged in pivoting fashion about the hinge axes.
The strips can have projections on the ends lying in the transverse direction of the chain, which engage correspondingly shaped grooves on the inside of the chain links between the joint sections. The grooves provided in all chain links of a chain series can also be used to mount other parts between the chain straps.
The energy guiding chains according to the invention can consist of inner and outer straps, as well as angled chain links. The cross-members can in each case be mounted in detachable fashion on the side straps or integrally molded on them, or they can be of such a width that they form a closed channel. The joint connections can be of any design, such as integral hinges or the like.